#!/bin/bash
#author:倔强的强

a=100
b=10
#val=`expr $a + $b`#一定加空格
#echo "a+b=$val"
echo "a+b=`expr $a + $b`"
echo "a-b=`expr $a - $b`"
echo "a*b=`expr $a \* $b`"
echo "a/b=`expr $a / $b`"
echo "a%b=`expr $a % $b`"

if [ $a == $b ]
then
    echo "a等于b"
fi
if [ $a != $b ]
then
    echo "a不等于b"
fi